Safety device for shearing or punching machines or the like



y 31, 1932- c. CARROLL ET AL 1,360,991

SAFETY DEVICE.FOR SHEARING' OR PUNCHING MACHINES OR THE LIKE Filed June 2, 1928 2 SheetsSheet l INYNTUF6 TTGRNEYS y 31, 1932- c. CARROLL ET AL 1 SAFETY DEVICE FOR SHEARING OR PUNCHING MACHINES OR THE LIKE 2 Sheets-Sheet 2 Filed June 2, 1928 WIT/V555 Patented May 31, 1932 Parent or F'EJC CHARLESCARROIIL,OFTEAST CHiECAiGOQAND JESSIESHERMAN HOG-TIE, OF HAMMOND,

INDIANA jeicts, advantages andinove'l features of design,

SAFETY" DEVICE non sHnAazme on i Application filed: June 2,

Among the obj ects-of our invention. are'to provide asafetyr'device:oranechanism suitable for: operative ilSSOCiiLtlOIL and .COIIlblIlil'lJlOIl.

witli a machinesuch as a shear, punch or the 4 like, embodyingi'a; movable 1 head carrying a blade orotherr shearing, cutting: or punching tool; saids device comprising means adapted tostrike-the operatorls hands if they are advanceditoo iclosclyr to the tool carryinghead before the latter can be set 1n n1otion=tothere by. warn the operatorofhm dangerand which,

furthermore; is: operative under such conditio11s= to-prevent the headifrom being set'in' motion untilv the operators hands are w1th-- 1 drawn to positioni'of safety.

A; furthen'obj ect ofthei invention is -to pro vide a safety. device of thecharacteraforesald operative to prevent the tool carryinghead of: the machine from. being? set in motion eX- cept whenaplate orother like article which is to be acted :uponby the toolis disposedlon the table of. the machine substantially inv shearing: position.

The invention; further contemplates the provision: of? a safety device for shearing. or l punchingmachmes or the like wh ch ls-off simple and rugged" construction and entirely automatic in the'performancc oftitsintended functions, which may be easily installed. on such machines and' other substant1ally SlIIIl lar' machines of the. types-commonly in use without? material: modification thereof and at: relatively slight; expense; and; which when so installed requires practically no attention construction and L arrangement to which :reference is more partlcularlyimadeor whichlwill be apparent from the following description of" one embodiment of' the. IHVEHJHOII as 1llus-- trated in the accompanying drawings.

As the invention;particularly lends itself to installation, upon and operative combina.- tion with shears adaptedfor'shearing plates;

sheets I orv similar: articles;.we have chose-nto illustrate'it in connection with a. plate shear PUNCHING MA-(LIBZIWES OR THE LIKE 1928: Serial No. 282/128 of: well known. form, and as the constructions and operation of shears of this character, are thoroughly familiar to those skilled in the art? we have shown in'the drawings ina somewhat conventional way only so much of; the shearuproper as is requisite foran adequate understandingof the invention. In thesaid drawings Fig; 1 is a front. view of the shear with the safety device operativelycombined therewith-andwith a-plate disposed ontheshear table in position to be acted upon byv the shear andiEig. 2 is an elevation of the left hand endof theshear, shown in Fig. 11;; in bothrofthese views the shear blade is shown.

' in raisedor normal position; Fig.1 3 isan enlarged fragmentary detail view, princi pally in verticalsection, of the clutch mechanism, andadjacent parts of the sheanyFig. e is. an enlarged fragmentary detail view, partially insect-ion, of a portion of the safety device apart froin the shear andFig. 5 is a diagrammatic View illustrating-the electrical connections: and mechanisms preferablyemployed in thedevice. Thesame symbols are usedrto designatethe same parts in the several. figures. 1

The particular plate. shear. shown comprises,-, generally. speaking, a table 1v disposed infront: of andibetween laterally spaced housings 2, 2lrisingzfrom arbase 3 and connected. at their. upper extremities by a heavy yoke 45. Between the housings is arranged. a: tool carrying head. or slide 5 vertically movable in'ways formed in thehousings and: actuated by cranks 6. in conjunction with eccentrics disposed on the main operating shaft? extending horizontally. throughand' journaledi in therhousings' above the head.- 'Eliis-shaftthrough suitable clutch mecha v nismherei'natter more particularly described maybeoperatively COIlIlQCtGClzWlth aipower" shaft 8 carrying a driving gearr 9 actuated from a motor: 10 or: other source ofipower through a gear train1l;the-motor and train are not: shownin the principals figuresbut areindicatedin F ig;.5'=and itwillvbe-undcr stoodthey may be of: any. desired arrange ment" and: construction effective" to keep the 2 power; shaft 8 rotating; continuously: when ever the motorisyinioperation. Thelower or stationary shear blade 12 is removably secured in horizontal transversely extending position adjacent the rear edge of the table and a complementary upper or movable shear blade 13 is similarly secured adjacent the lower edge of the head which is prefer ab] 1 angularly upwardly inclined from one end to the other so that as it descends from normal position and carries the upper blade over the adjacent face of the lower one, the overhanging end P of a plate P disposed on the table will be progressively sheared from one lateral edge to the other. As plate shears of this general character are in common use and well understood by those familiar with the art further description would be superfluous.

It will of course be appreciated that when the power shaft 8 is disconnected from the operating shaft 7 no movement of the head 5 can take place but that when such connection is effected between the shafts through the medium of the clutch, the rotation of shaft 7' thus brought about is effective to reciprocate the head. The clutch is preferably so constructed that each time it is engaged one full revolution is imparted to the operating shaft with the result that if the head be in raised position at the commencement of the revolution of the shaft, it is given a full movement of reciprocation in both directions and thus returned toinormal position simultaneously with the automatic disengagement of the clutch when the operating shaft has completed a full revolution.

\Vhile various types of clutches and clutch operating mechanism adapted for the performance of these functions are in use, one well known form thereof which we have chosen to illustrate comprises, as best shown in Fig. 3, a clutch-half 2O keyed to shaft 7 and carrying in a recess formed in its outer face a spring pressed pin 21 having a suitably beveled or tapered end. This pin is operative when projected out of itsrecess to engage in any one of a series of depressions 23 formed in a clutch plate 24 carried by the driving gear 9 so as to lock the clutch-half 20 to the plate and thus effect revolution of shaft 7. For disengaging the pin from the plate and thereafter holding it in its recess to maintain the clutch in disengaged condition, a dog 25 is disposed adjacent the forward end of an arm 26 carried by a lever 27 pivoted to the frame of the machine at 28; this dog has a suitably beveled face and,

i when the lever is raised, is adapted to enter between the clutch-half 20 and plate 24 and lie in the path of the pin as it is carried around when the clutch as a whole is rotatin so that after the pin reaches the dog it ri es up on the beveled face thereof and is thus forced out of engagement with plate 24 with resultant disengagement of the clutch, the dog thereafter operating to hold the pin in its recess as shown in Fig. 3 until it is moved away from the pin by actuation of lever 27. This movement of the lever is effected through the medium of a link 30 having in accordance with our invention a pin and slot connection 31 with an arm 32 disposed on a shaft 33 extending horizontally adjacent the base of the machine and also carrying operating pedals 34. Thus, when it'is desired to engage the clutch, the operator by depressing one of the pedals 34 can move the link upwardly so as to rotate lever 27 on its fulcrum, after the lost motion permitted by the pin and slot connection 31 is taken up, and thereby withdraw dog 25 from between clutch-half 20 and plate 24 to permit pin 21 to move outwardly in its recess and enter one of the depressions in the plate which, with the gear 9, is constantly rotating. As soon as the clutch is thus engaged the operator removes his foot from the pedal which allows the dog to move upwardly into the path of the pin which, as the shaft 7 approaches completion of a full revolution, gradually rides up on the dog and is ultimately forced out of engagement with plate 24, thereby disengaging the clutch and returning the parts to the position shown in Fig. 3. Save for the use of the pin and slot, instead of a direct connection between link 30 and arm 32, the parts hitherto described are of usual and well known construction and operation.

In accordance with the present invention we dispose in front of the head 5 and upper blade 13 a vertically movable guard generally designated as 35 comprising a horizontally extending support 36, which for lightness and strength may be tubular, and depending portions 37 desirably of wire netting or the like carried on suitable frames suspended from the supports by clips or bands 38 through which the support extends in such manner that the depending portions will. hang vertically from the supports and can swing about the latter, though in certain constructions it may be preferable to permanently sccure the clips to the supports so as to hold the depending portions rigidly in substantially vertical position.

The guard is supported by a pair of laterally spaced substantially vertically extending tubes 40, 41 whose lower ends pass through bosses 36' in the supports and are welded or otherwise secured thereto. These tubes extend upwardly from the guard through guides 42 carried by the head 5 and near their upper ends are respectively provided with slots 40, 41 through which are extended the free forward ends of arms =13, 44 which are mounted on a shaft 45 journaled in brackets 46 extending rearwardly from the yoke 4 of the shear. To hold the tubes in proper position on the arms and form a sort of guide therefor, pins 43, 44 are extended throughthe arms on opposite sides of the ad-v jacent tube, thearespect-ive pairsof pins being spacediapart sufliciently,however, to permit the-arms to move freely in the slots in the tubes when the arms are oscillatedthrough a limited are as hereinafter described. Upon the shaft adjacent the lefthand end ofthe machine is also mounted a crankt'? connected'by a link 48 withrthe rear end of the arm 32, a. turn buckle 48 being desirably providedin'the link to enable theconvenient djustment of itslength. It. will thus be apparent-that when the pedals 34are in normal or, raised position as shown the forward or free ends of the arms 43, 44 will also be raised and the tubes 40, 4:1 suspended thereon through engagement of the upper ends of the slots in the tubeswith the levers, thus in turn holding the tubes in raised position.

Disposedin the, lower end of each tube is a contact point insulated from the tube by aninsulating bushing 51 and connected ample,that carriedby tubeO, isablock 52,

of fibre or other insulating material against which when the guard i1s lowered the superjacentcontact polnt will engage in the absence of a plate P or other article on the table in the path of the'point;

It will thus be apparent that depression of either of the pedals 34; from raised or normal position is initi ally eiiective to move arms 43,

44: downward, thus allowing the guard 35 to descend'by gravity as the tubes 40, 1-1 follow the arms, untilone COIltElCbPOlllt strllzes the fibre block 52 and the other strikes the table 1, assuming there is no plate in the latter, ithus arresting further downward movement of the uard but the movement of the pedal requisite for accomplishing this result is in- 'suf'ficient'rto move the link 30 since the. parts all are so arranged and adjusted that during 1'; or at least the major portion of the downwa d movement of the. guard the pin 31 of the slot and pin connection 31 between the arm 32 and link 30 merely rises in'the slot and is thus inefiective to move the link. However,

- about the time the guard reaches its lowerdraw dog 25 frombetween the members of the clutchand allow pin 21 to move outward to lock clutch-half 20 to the rotating gear 9, the arms 43, 44 during this furtherv movement of the pedal merely traveling downward in the slots 40, 41 inthe now stationary tubes to whatever extent may be required, the length of the slots being ample for this purpose.

In accordance with our invention means are provithd for positively preventing engagciucnt of the clutch until the guard has reached'or substantially reached lowered position and the contact points are resting on a plate or other like article disposedupon the table'of the machine beneath the guard; a preferred form of said means, which are both electrical and inechanicallin character, will now be describedf Disposed on that housing of the shear adjacent tie clutch or in any other convenient position is a bracket carryinga solenoid tilthe plunger of which is connected with a toothed locking dog 62 pivoted to thebracket as at 68 and cooperative with a correspond,-

ingly toothed rack adjacent the lower end of a rod 64 vertically slidable through arms 60 with which the bracket is provided, theupper end of this rod being pivotally connected to the lever 27. A spring 65 is disposed adjacent dog 62 in such manner. as to constantly force it toward the rod and engage its teeth with those of the latter when the solenoid is unenergized, thus preventing rod 64 from vertical movement and holding lever 27' in raised position, thereby maintaining dog, 25 in position to hold pin 21 out of engagement with plate 2d on the driving gear. When, however, the solenoid is energized as herein-r after described, dog 62 is'moved to the right in Fig. 1 so as to disengage its teeth from those on rod 64, thus unlocking lever 27 and permitting it to move downwardly to withdraw the dog 25. from pin-engaging position. Reference may now be had to Fig. 5 for an explanation of the electrical connections and mechanisms preferably employed and which, a

in addition to the solenoid 61, may comprise a relay and two separate circuits now to be descrlbed. In the first or relay circuit which may desirably be of relatively low another wire 74 from the latter, through switch 72, completes the circuit back to the source of current. In the second or solenoid circuit which may be of higher voltage, a wire extends through a switch 81 from a suitable source of current to the solenoid 61; a wire 82 extends fromthe solenoid to the relay ?0 and another wire 83 extends fromrthe other side oft-he relay to theswitch a-ndthence;

vgization ofthe solenod 6.

completes-the circuit to the source of current su ply.

he operation of the invention when constructed and installed substantially as hereinbefore described will now be briefly explained: When, as shown, the movable tool carrying head 5, guard and operating pedals 34 are all in raised or normal position the dog is so disposed as to hold pin 21 out of engagement with sliding gear 9 and thus maintain the clutch disengaged. Assuming the gear 9 is rotating and that a plate P disposed on the table of the shear has been advanced to shearing position in which its forward cdge P overhangs the stationary blade 12, the operator now depresses one of the pedals 34 which, as heretofore explained, is initially eflective to move the guard down until the contact points engage the surface of the 20 plate, thus effecting a connection between the points through the. medium of the plate itself and completing the circuit through the coil of relay which immediately operates to close solenoid circuit with resultant ener- Thus energized, the solenoid moves dog 62 away from. rod 6e and unlocks lever 27 so that the downward movement of pedal 34 is continued by the operator, lever 27 can rotate about its pivot to withdraw dog 25 from, the path of pin 21 and permit engagement of the clutch, thereby initiating the downward movement of the head 5 carrying blade 13. Toward the completion of the shearing operation the operator removes his foot from the pedal which imn'icdiately returns to normal position, thus raising the guard, breaking the circuit between the points, (lo-energizing the solenoid, and also moving lever 27 to a position in which dog 25 is again interposed in the path of the pin as it moves around with the clutch; as shaft 7 approaches completion of a full revolution pin 21 begins to ride up on the dog as heretofore explained and as the shaft completes its revolution the pin is forced out of engagement with plate 24 by the dog so as to disengage the clutch and bring the parts to rest with the head in elevated position and the locking dog again locking rod 64 against movement.

It will be apparent from the foregoing that until the two contact points 50 are brought into engagement with plate P the circuits are kept open and the solenoid maintained in deenergized condition with the result that it is impossible to engage the clutch. Consequently, if the operators hands are too close to the path of the shear blade when he depresses the operating pedal they will necessarily lie in the. path of the guard and will be struck by the latter during its descent and before any movement of the blade, thus giving the operator a tangible and physical warning that his hands are in danger and,

sufliciently far to bring the contact points into engagement with the plate P until the are withdrawn from beneath the guar Therefore, not only is a. careless operator his hands are completely withdrawn from the path of the guard so the latter can descend suiiiciently to establish through the plate itself the circuit which is necessarily prerequisite to the engagement of the main clutch of the machine. I

It will be further apparent that the pres ence of a plate in a position to be engaged by both contact points is required before any engagement of the clutch can be effected, for in the absence of the plate the contact point aligned with the insulating block 52 will merely engage the latter when the guard is full lowered and no circuit will be established between the points. The employment of the block istherefore advantageous in that it tends to prevent unauthorized operation of the machine or its operation and consequent consumption of power when no plate is in position to be sheared, and also tends to minimize the chance of injury through accidental operation of the machine when making adjustments or the like.

The use of separate relay and solenoid circuits as herein explained is ordinarily deemed preferable by us since the use of current of relatively high voltage for operating the solenoid without danger to the operator of the machine is thereby permitted. Thus, for example, by the use of separate circuits as aforesaid, direct current at a voltage of may be employed for the operation of the solenoid and alternating current at a voltage of 110 in the relay circuit, thus avoiding any chance of injury to the operator should he bring his hands into contact with any of the exposed parts of the latter such as the contact points. Under certain circumstances, however, it may be preferred to include both the solenoid and the contact points in a single circuit thus dispensing with the relay and the separate relay circuit and utilizing the same voltage between the contact points as in the solenoid.

While we have herein described and illustrated with considerable detail a preferred embodiment of our invention in operative association and combination with a plate shear of well known form and embodying a clutch of the type frequently employed, we do not thereby desire or intend to limit or confine the use of our invention to plate or other shears as the same is equally adapted for use in connection with punching or form- I 06 further, prevent the guard from descending ing machines and in fact with any machine having a movable tool carrying head in proximity to which the operators hands are necessarily more or less adjacent during the cycle of its operations, while, additionally, the details of design, construction and arrangement of the various parts of the specific mechanism employed in the practice of the invention may be modified in numerous particulars from the precise embodiments to which we have referred with a view to adapting the same for installation upon and operative association with machines of variant construction or for other purposes as may be desired, without departing from the spirit and scope of the invention as defined in the appended claims.

Havingthus described our invention, we claim and desire to protect by Letters Patent of the United States:

1. In combination, a machine having a movable head, a clutch operative to control the movement of the head and a table adapted to receive an article to be operated on by the machine, an electrically conductive article, and a safety device comprising a movable guard, means for moving the guard to a point adjacent the table, and means operative to prevent engagement of the clutch to move the head. save when {said article is disposed on the table in the path of the guard.

2. In combination, a machine having a movable head, a clutch operative to control the movement of the head and a table adapted to receive the article to be acted on by the machine, an electrically conductive article, and a safety device comprising a vertically movable guard, means for lowering the guard to a point adjacent the table, means carried by the guard operative to contact with said article when disposed on the table beneath the guard, and means operative to prevent engagement of the clutch to move the head until after said contacting means are brought into engagement with said article.

3. The combination of a machine having a movable tool-carrying head, a clutch operative to control the movement of the head, means for engaging and disengaging the clutch and a table adapted to support an article to be acted on by a tool carriedby the head, an electrically conductive article, and a safety device comprising a vertically movable guard disposed in front of the path of the head, means interconnected with said clutch operating means operative to move the guard toward the table, spaced contact points carried by the guard, and electrically releasable locking means operative to prevent engagement of the clutch until said contact points are brought into such engagement with said article when disposed on the table beneath the guard as to thereby establish a circuit through said article.

4. Thecombinationof a mac'hine having :a movable tool-carrying head, a clutch operati-ve to control the 'movement 'of the head, mean's ifor-"engaging and -disengaging the :clutch and ta table adapted toPsupport. an ar- Tti'ClGTtO be acted onby aitool "carried bythe head, an :elec -i=cally-' conductive. article,:and avsafety device "comprisi ngia verti'cally' movable iguard disposed in ("front of the ihea d, "means interconnected with said clutch Lenligaging means operative to rmove the guard toward "the table upon initial actuation 1 of :said clutch engaging means, "spaced contact points *carried by Ethe guard, locking means adapted? to normally "preventengagementof $8 "the clutch, and electrically actuated :means operative to release said locking *means :to (permit engagement of the clutch fatter said contact points are brought into "contact with said article when disposed on the t'able i beneath the :guardand a: circuit 1 established through said article between said points.

i 5. The combination 0t armachine-having-a movable tool-carrying i head, clutch operative :to icontrol ithe :movement of the .head, i means ifor -2engagii;1g and disen gaging the clutch T and a table adapted :to support an article tdbeacted on-bya tool carried by' the head, an-electrically conductive article, and a-safetyi device comprising a movable guard, meansintercennected with the clutch engagingj means for moving the guard, loc'king means for the c'lutchengaging i means opera- .tive F to normally maintain the r clutch :disen- .gaged and electrically actuated means includingspaced -'contact points carried by :the guard operative to release said locking means to permitengagementbf the clutch when a circuit "is established between said points throughssaid article when disposed on: thePtabIeibeneath the guard.

6. The combin'ationof a machine having a movable tool-carrying head, -a clutch operativeito controltthe movement of the? head, means for --engaging and disengaging the clutch and a table i adapted to support an article to he acted r on -.by a .tool-tcarried by the head, an -electrically conduetive'article, and. a :safetydevice 1 comprising spaced contact points, means interconnected with the clutch :engagin-g means for moving said pointsinto contact with said article when disposedon the table to thereby establish a circuit between said points, lockingimeans operative to inormally prevent the engagement of the clutch, electric-ally "actuated means operative YtO release said locking means when said 'circuit is established between the points, and means carried by the table adapted to prevent the establishment of said circuit in the absence of said article.

7 The combination of a machine having a movable tool-carrying head, a clutch operative to control the movement of the head, means for engaging and disengaging the a6 meow-1 -,cl t h and aeta l u aptedtq supporta-n r- 7 .z1 i; t c e'to he acteduponby art ol a rled by th head,;a.n electrically.,con'duct v.e -artic1e;;.a-nd 1;; laesaiety deviee, comprising a yerticallyimovlqeblelguard disposed in'front ,of,.the-head e ,abo e the-table, .apairof spaced contact 7 points carried by theguard and depending '3 -therebelow,'means interconnected with/the clutch engaging means vadapted to.l0.wer.the i 1 guard towatclthe' table during the initial movement (ofusaid means to 'engagewga-id Lpoints withsaidurticle Whendisposed there- :on,;means opei ative'iton pi event engagement 1 I oftlme clutch during said'initial'movement, 16 and electi'i,callyv operated means adapted'to release said last mentioned means to permit engagement of 1 the clutch during subsequent movement ofthewclutchvope ating mean s J1 after the completion of a circuit between 'sa'id 90' intethrough theimedium ofsaid'iirticle'. :5. .1 e ee-.8'.I In a safety devicefora-machinehaving a a indvable" tool-carrying heacL- a pajir of spaoedconte'ct points, amovable'locking dog, 1i means for normally holding the dogin lockinghpositin, a circuit including said contact pointsqandnormally interruptedbetween the'latt'e'p, a solenoid connected with thelocking flog whereby completion of the circuit between the contact points i's operatiye to u:

nctuatethe s'olenoid -to move the locking dog from locking position and means other than the; dog, 'a1dapted to be maintained in non-operable condition when the leeking V. i dog isin locking position'andoperable to efiectmoyement of the head when theloeklin' dog -i s m'oved from lockiiig osition: 92 111 cembilmtion a machinehaving -e I table; an electricallyconduetiveei ticleito be actedupon byjthemachine,and a safety 2;

device-comprisinga movable guard, a pair of spaced A contact poin'te movable' with the ,e

gumi meensior moving theguard, a niovv V ablelooking dog; ai cii'cuit"-includ-ing-jsaid p ints-fund nq rmall "interruptedfbetween ,1;

145 the lstter a-solenoidconnected with the l0ckingfiogLandwpe-r'able to withdraw the dog from lockingposition; and 'meens for noi F many holding" the dog in locking position when said circuit 'is'jopemwhereby upen clos mg of the circuit bye movement of the guard operativegto engagegsaid poi-mswwith sgm urticle when disposed tIm S'aidtabIe the f Solenoidis energized to move the l dog'jfroni f:

495 rInawimesswhere Lwehave hamme s-net own-hand 'this21st{day 0fMuy; 1928i 5 CI-IARIJES- 'GARROLLf-i 

